<!-- HTML header for doxygen 1.8.6-->
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/xhtml;charset=UTF-8"/>
<meta http-equiv="X-UA-Compatible" content="IE=9"/>
<meta name="generator" content="Doxygen 1.8.13"/>
<title>OpenCV: samples/cpp/laplace.cpp</title>
<link href="../../opencv.ico" rel="shortcut icon" type="image/x-icon" />
<link href="../../tabs.css" rel="stylesheet" type="text/css"/>
<script type="text/javascript" src="../../jquery.js"></script>
<script type="text/javascript" src="../../dynsections.js"></script>
<script type="text/javascript" src="../../tutorial-utils.js"></script>
<link href="../../search/search.css" rel="stylesheet" type="text/css"/>
<script type="text/javascript" src="../../search/searchdata.js"></script>
<script type="text/javascript" src="../../search/search.js"></script>
<script type="text/x-mathjax-config">
  MathJax.Hub.Config({
    extensions: ["tex2jax.js", "TeX/AMSmath.js", "TeX/AMSsymbols.js"],
    jax: ["input/TeX","output/HTML-CSS"],
});
//<![CDATA[
MathJax.Hub.Config(
{
  TeX: {
      Macros: {
          matTT: [ "\\[ \\left|\\begin{array}{ccc} #1 & #2 & #3\\\\ #4 & #5 & #6\\\\ #7 & #8 & #9 \\end{array}\\right| \\]", 9],
          fork: ["\\left\\{ \\begin{array}{l l} #1 & \\mbox{#2}\\\\ #3 & \\mbox{#4}\\\\ \\end{array} \\right.", 4],
          forkthree: ["\\left\\{ \\begin{array}{l l} #1 & \\mbox{#2}\\\\ #3 & \\mbox{#4}\\\\ #5 & \\mbox{#6}\\\\ \\end{array} \\right.", 6],
          forkfour: ["\\left\\{ \\begin{array}{l l} #1 & \\mbox{#2}\\\\ #3 & \\mbox{#4}\\\\ #5 & \\mbox{#6}\\\\ #7 & \\mbox{#8}\\\\ \\end{array} \\right.", 8],
          vecthree: ["\\begin{bmatrix} #1\\\\ #2\\\\ #3 \\end{bmatrix}", 3],
          vecthreethree: ["\\begin{bmatrix} #1 & #2 & #3\\\\ #4 & #5 & #6\\\\ #7 & #8 & #9 \\end{bmatrix}", 9],
          cameramatrix: ["#1 = \\begin{bmatrix} f_x & 0 & c_x\\\\ 0 & f_y & c_y\\\\ 0 & 0 & 1 \\end{bmatrix}", 1],
          distcoeffs: ["(k_1, k_2, p_1, p_2[, k_3[, k_4, k_5, k_6 [, s_1, s_2, s_3, s_4[, \\tau_x, \\tau_y]]]]) \\text{ of 4, 5, 8, 12 or 14 elements}"],
          distcoeffsfisheye: ["(k_1, k_2, k_3, k_4)"],
          hdotsfor: ["\\dots", 1],
          mathbbm: ["\\mathbb{#1}", 1],
          bordermatrix: ["\\matrix{#1}", 1]
      }
  }
}
);
//]]>
</script><script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/mathjax/2.7.0/MathJax.js"></script>
<link href="../../doxygen.css" rel="stylesheet" type="text/css" />
<link href="../../stylesheet.css" rel="stylesheet" type="text/css"/>
</head>
<body>
<div id="top"><!-- do not remove this div, it is closed by doxygen! -->
<div id="titlearea">
<!--#include virtual="/google-search.html"-->
<table cellspacing="0" cellpadding="0">
 <tbody>
 <tr style="height: 56px;">
  <td id="projectlogo"><img alt="Logo" src="../../opencv-logo-small.png"/></td>
  <td style="padding-left: 0.5em;">
   <div id="projectname">OpenCV
   &#160;<span id="projectnumber">4.5.2</span>
   </div>
   <div id="projectbrief">Open Source Computer Vision</div>
  </td>
 </tr>
 </tbody>
</table>
</div>
<!-- end header part -->
<!-- Generated by Doxygen 1.8.13 -->
<script type="text/javascript">
var searchBox = new SearchBox("searchBox", "../../search",false,'Search');
</script>
<script type="text/javascript" src="../../menudata.js"></script>
<script type="text/javascript" src="../../menu.js"></script>
<script type="text/javascript">
$(function() {
  initMenu('../../',true,false,'search.php','Search');
  $(document).ready(function() { init_search(); });
});
</script>
<div id="main-nav"></div>
</div><!-- top -->
<!-- window showing the filter options -->
<div id="MSearchSelectWindow"
     onmouseover="return searchBox.OnSearchSelectShow()"
     onmouseout="return searchBox.OnSearchSelectHide()"
     onkeydown="return searchBox.OnSearchSelectKey(event)">
</div>

<!-- iframe showing the search results (closed by default) -->
<div id="MSearchResultsWindow">
<iframe src="javascript:void(0)" frameborder="0" 
        name="MSearchResults" id="MSearchResults">
</iframe>
</div>

<div class="header">
  <div class="headertitle">
<div class="title">samples/cpp/laplace.cpp</div>  </div>
</div><!--header-->
<div class="contents">
<p>An example using Laplace transformations for edge detection</p>
<div class="fragment"><div class="line"><span class="preprocessor">#include &quot;<a class="code" href="../../dc/d3d/videoio_8hpp.html">opencv2/videoio.hpp</a>&quot;</span></div><div class="line"><span class="preprocessor">#include &quot;<a class="code" href="../../d4/dd5/highgui_8hpp.html">opencv2/highgui.hpp</a>&quot;</span></div><div class="line"><span class="preprocessor">#include &quot;<a class="code" href="../../d1/d4f/imgproc_2include_2opencv2_2imgproc_8hpp.html">opencv2/imgproc.hpp</a>&quot;</span></div><div class="line"></div><div class="line"><span class="preprocessor">#include &lt;ctype.h&gt;</span></div><div class="line"><span class="preprocessor">#include &lt;stdio.h&gt;</span></div><div class="line"><span class="preprocessor">#include &lt;iostream&gt;</span></div><div class="line"></div><div class="line"><span class="keyword">using namespace </span><a class="code" href="../../d2/d75/namespacecv.html">cv</a>;</div><div class="line"><span class="keyword">using namespace </span><a class="code" href="../../d8/dcc/namespacestd.html">std</a>;</div><div class="line"></div><div class="line"><span class="keyword">static</span> <span class="keywordtype">void</span> help(<span class="keywordtype">char</span>** argv)</div><div class="line">{</div><div class="line">    cout &lt;&lt;</div><div class="line">            <span class="stringliteral">&quot;\nThis program demonstrates Laplace point/edge detection using OpenCV function Laplacian()\n&quot;</span></div><div class="line">            <span class="stringliteral">&quot;It captures from the camera of your choice: 0, 1, ... default 0\n&quot;</span></div><div class="line">            <span class="stringliteral">&quot;Call:\n&quot;</span></div><div class="line">         &lt;&lt;  argv[0] &lt;&lt; <span class="stringliteral">&quot; -c=&lt;camera #, default 0&gt; -p=&lt;index of the frame to be decoded/captured next&gt;\n&quot;</span> &lt;&lt; endl;</div><div class="line">}</div><div class="line"></div><div class="line"><span class="keyword">enum</span> {GAUSSIAN, BLUR, MEDIAN};</div><div class="line"></div><div class="line"><span class="keywordtype">int</span> sigma = 3;</div><div class="line"><span class="keywordtype">int</span> smoothType = GAUSSIAN;</div><div class="line"></div><div class="line"><span class="keywordtype">int</span> main( <span class="keywordtype">int</span> argc, <span class="keywordtype">char</span>** argv )</div><div class="line">{</div><div class="line">    <a name="_a0"></a><a class="code" href="../../d0/d2e/classcv_1_1CommandLineParser.html">cv::CommandLineParser</a> parser(argc, argv, <span class="stringliteral">&quot;{ c | 0 | }{ p | | }&quot;</span>);</div><div class="line">    help(argv);</div><div class="line"></div><div class="line">    <a name="_a1"></a><a class="code" href="../../d8/dfe/classcv_1_1VideoCapture.html">VideoCapture</a> cap;</div><div class="line">    <span class="keywordtype">string</span> camera = parser.<a name="a2"></a><a class="code" href="../../d0/d2e/classcv_1_1CommandLineParser.html#a190215863579a6d244dccfd261ee0224">get</a>&lt;<span class="keywordtype">string</span>&gt;(<span class="stringliteral">&quot;c&quot;</span>);</div><div class="line">    <span class="keywordflow">if</span> (camera.size() == 1 &amp;&amp; isdigit(camera[0]))</div><div class="line">        cap.<a name="a3"></a><a class="code" href="../../d8/dfe/classcv_1_1VideoCapture.html#a614a1702e15f42ede5100014ce7f48ed">open</a>(parser.<a class="code" href="../../d0/d2e/classcv_1_1CommandLineParser.html#a190215863579a6d244dccfd261ee0224">get</a>&lt;<span class="keywordtype">int</span>&gt;(<span class="stringliteral">&quot;c&quot;</span>));</div><div class="line">    <span class="keywordflow">else</span></div><div class="line">        cap.<a class="code" href="../../d8/dfe/classcv_1_1VideoCapture.html#a614a1702e15f42ede5100014ce7f48ed">open</a>(<a name="a4"></a><a class="code" href="../../d6/dba/group__core__utils__samples.html#ga4a37595bcd267558bd6c176c7307f050">samples::findFileOrKeep</a>(camera));</div><div class="line">    <span class="keywordflow">if</span> (!cap.<a name="a5"></a><a class="code" href="../../d8/dfe/classcv_1_1VideoCapture.html#a9d2ca36789e7fcfe7a7be3b328038585">isOpened</a>())</div><div class="line">    {</div><div class="line">        cerr &lt;&lt; <span class="stringliteral">&quot;Can&#39;t open camera/video stream: &quot;</span> &lt;&lt; camera &lt;&lt; endl;</div><div class="line">        <span class="keywordflow">return</span> 1;</div><div class="line">    }</div><div class="line">    cout &lt;&lt; <span class="stringliteral">&quot;Video &quot;</span> &lt;&lt; parser.<a class="code" href="../../d0/d2e/classcv_1_1CommandLineParser.html#a190215863579a6d244dccfd261ee0224">get</a>&lt;<span class="keywordtype">string</span>&gt;(<span class="stringliteral">&quot;c&quot;</span>) &lt;&lt;</div><div class="line">        <span class="stringliteral">&quot;: width=&quot;</span> &lt;&lt; cap.<a name="a6"></a><a class="code" href="../../d8/dfe/classcv_1_1VideoCapture.html#aa6480e6972ef4c00d74814ec841a2939">get</a>(<a name="a7"></a><a class="code" href="../../d4/d15/group__videoio__flags__base.html#ggaeb8dd9c89c10a5c63c139bf7c4f5704dab26d2ba37086662261148e9fe93eecad">CAP_PROP_FRAME_WIDTH</a>) &lt;&lt;</div><div class="line">        <span class="stringliteral">&quot;, height=&quot;</span> &lt;&lt; cap.<a class="code" href="../../d8/dfe/classcv_1_1VideoCapture.html#aa6480e6972ef4c00d74814ec841a2939">get</a>(<a name="a8"></a><a class="code" href="../../d4/d15/group__videoio__flags__base.html#ggaeb8dd9c89c10a5c63c139bf7c4f5704dad8b57083fd9bd58e0f94e68a54b42b7e">CAP_PROP_FRAME_HEIGHT</a>) &lt;&lt;</div><div class="line">        <span class="stringliteral">&quot;, nframes=&quot;</span> &lt;&lt; cap.<a class="code" href="../../d8/dfe/classcv_1_1VideoCapture.html#aa6480e6972ef4c00d74814ec841a2939">get</a>(<a name="a9"></a><a class="code" href="../../d4/d15/group__videoio__flags__base.html#ggaeb8dd9c89c10a5c63c139bf7c4f5704dadadc646b31cfd2194794a3a80b8fa6c2">CAP_PROP_FRAME_COUNT</a>) &lt;&lt; endl;</div><div class="line">    <span class="keywordtype">int</span> pos = 0;</div><div class="line">    <span class="keywordflow">if</span> (parser.<a name="a10"></a><a class="code" href="../../d0/d2e/classcv_1_1CommandLineParser.html#a8c41cf242b2ad8c0472e3b57893ef200">has</a>(<span class="stringliteral">&quot;p&quot;</span>))</div><div class="line">    {</div><div class="line">        pos = parser.<a class="code" href="../../d0/d2e/classcv_1_1CommandLineParser.html#a190215863579a6d244dccfd261ee0224">get</a>&lt;<span class="keywordtype">int</span>&gt;(<span class="stringliteral">&quot;p&quot;</span>);</div><div class="line">    }</div><div class="line">    <span class="keywordflow">if</span> (!parser.<a name="a11"></a><a class="code" href="../../d0/d2e/classcv_1_1CommandLineParser.html#ad6b244a52f3b90da6fc463341c8a486f">check</a>())</div><div class="line">    {</div><div class="line">        parser.<a name="a12"></a><a class="code" href="../../d0/d2e/classcv_1_1CommandLineParser.html#a70c31969ec5259b8c093d11a80c34f9f">printErrors</a>();</div><div class="line">        <span class="keywordflow">return</span> -1;</div><div class="line">    }</div><div class="line"></div><div class="line">    <span class="keywordflow">if</span> (pos != 0)</div><div class="line">    {</div><div class="line">        cout &lt;&lt; <span class="stringliteral">&quot;seeking to frame #&quot;</span> &lt;&lt; pos &lt;&lt; endl;</div><div class="line">        <span class="keywordflow">if</span> (!cap.<a name="a13"></a><a class="code" href="../../d8/dfe/classcv_1_1VideoCapture.html#a8c6d8c2d37505b5ca61ffd4bb54e9a7c">set</a>(<a name="a14"></a><a class="code" href="../../d4/d15/group__videoio__flags__base.html#ggaeb8dd9c89c10a5c63c139bf7c4f5704da6223452891755166a4fd5173ea257068">CAP_PROP_POS_FRAMES</a>, pos))</div><div class="line">        {</div><div class="line">            cerr &lt;&lt; <span class="stringliteral">&quot;ERROR: seekeing is not supported&quot;</span> &lt;&lt; endl;</div><div class="line">        }</div><div class="line">    }</div><div class="line"></div><div class="line">    <a name="a15"></a><a class="code" href="../../d7/dfc/group__highgui.html#ga5afdf8410934fd099df85c75b2e0888b">namedWindow</a>(<span class="stringliteral">&quot;Laplacian&quot;</span>, <a name="a16"></a><a class="code" href="../../d0/d90/group__highgui__window__flags.html#ggabf7d2c5625bc59ac130287f925557ac3acf621ace7a54954cbac01df27e47228f">WINDOW_AUTOSIZE</a>);</div><div class="line">    <a name="a17"></a><a class="code" href="../../d7/dfc/group__highgui.html#gaf78d2155d30b728fc413803745b67a9b">createTrackbar</a>(<span class="stringliteral">&quot;Sigma&quot;</span>, <span class="stringliteral">&quot;Laplacian&quot;</span>, &amp;sigma, 15, 0);</div><div class="line"></div><div class="line">    <a name="_a18"></a><a class="code" href="../../d3/d63/classcv_1_1Mat.html">Mat</a> smoothed, laplace, result;</div><div class="line"></div><div class="line">    <span class="keywordflow">for</span>(;;)</div><div class="line">    {</div><div class="line">        <a class="code" href="../../d3/d63/classcv_1_1Mat.html">Mat</a> frame;</div><div class="line">        cap &gt;&gt; frame;</div><div class="line">        <span class="keywordflow">if</span>( frame.empty() )</div><div class="line">            <span class="keywordflow">break</span>;</div><div class="line"></div><div class="line">        <span class="keywordtype">int</span> ksize = (sigma*5)|1;</div><div class="line">        <span class="keywordflow">if</span>(smoothType == GAUSSIAN)</div><div class="line">            <a name="a19"></a><a class="code" href="../../d4/d86/group__imgproc__filter.html#gaabe8c836e97159a9193fb0b11ac52cf1">GaussianBlur</a>(frame, smoothed, <a name="a20"></a><a class="code" href="../../dc/d84/group__core__basic.html#ga346f563897249351a34549137c8532a0">Size</a>(ksize, ksize), sigma, sigma);</div><div class="line">        <span class="keywordflow">else</span> <span class="keywordflow">if</span>(smoothType == BLUR)</div><div class="line">            <a name="a21"></a><a class="code" href="../../d4/d86/group__imgproc__filter.html#ga8c45db9afe636703801b0b2e440fce37">blur</a>(frame, smoothed, <a class="code" href="../../dc/d84/group__core__basic.html#ga346f563897249351a34549137c8532a0">Size</a>(ksize, ksize));</div><div class="line">        <span class="keywordflow">else</span></div><div class="line">            <a name="a22"></a><a class="code" href="../../d4/d86/group__imgproc__filter.html#ga564869aa33e58769b4469101aac458f9">medianBlur</a>(frame, smoothed, ksize);</div><div class="line"></div><div class="line">        <a name="a23"></a><a class="code" href="../../d4/d86/group__imgproc__filter.html#gad78703e4c8fe703d479c1860d76429e6">Laplacian</a>(smoothed, laplace, <a name="a24"></a><a class="code" href="../../d1/d1b/group__core__hal__interface.html#ga9d2ee1a8334733dea7482a47a88e0f87">CV_16S</a>, 5);</div><div class="line">        <a name="a25"></a><a class="code" href="../../d2/de8/group__core__array.html#ga3460e9c9f37b563ab9dd550c4d8c4e7d">convertScaleAbs</a>(laplace, result, (sigma+1)*0.25);</div><div class="line">        <a name="a26"></a><a class="code" href="../../d7/dfc/group__highgui.html#ga453d42fe4cb60e5723281a89973ee563">imshow</a>(<span class="stringliteral">&quot;Laplacian&quot;</span>, result);</div><div class="line"></div><div class="line">        <span class="keywordtype">char</span> c = (char)<a name="a27"></a><a class="code" href="../../d7/dfc/group__highgui.html#ga5628525ad33f52eab17feebcfba38bd7">waitKey</a>(30);</div><div class="line">        <span class="keywordflow">if</span>( c == <span class="charliteral">&#39; &#39;</span> )</div><div class="line">            smoothType = smoothType == GAUSSIAN ? BLUR : smoothType == BLUR ? MEDIAN : GAUSSIAN;</div><div class="line">        <span class="keywordflow">if</span>( c == <span class="charliteral">&#39;q&#39;</span> || c == <span class="charliteral">&#39;Q&#39;</span> || c == 27 )</div><div class="line">            <span class="keywordflow">break</span>;</div><div class="line">    }</div><div class="line"></div><div class="line">    <span class="keywordflow">return</span> 0;</div><div class="line">}</div></div><!-- fragment --> </div><!-- contents -->
<!-- HTML footer for doxygen 1.8.6-->
<!-- start footer part -->
<hr class="footer"/><address class="footer"><small>
Generated on Fri Apr 2 2021 11:36:29 for OpenCV by &#160;<a href="http://www.doxygen.org/index.html">
<img class="footer" src="../../doxygen.png" alt="doxygen"/>
</a> 1.8.13
</small></address>
<script type="text/javascript">
//<![CDATA[
addTutorialsButtons();
//]]>
</script>
</body>
</html>
